1. Field of the Invention
The present invention relates to a heat dissipation configuration of a semiconductor element mounted on a wiring board, and a method for manufacturing the same.
2. Description of Related Art
A configuration that allows heat generated from an active element region of a semiconductor element mounted on a wiring board to dissipate on the wiring board is disclosed in, for example, JP 10-65072 A (Patent Document 1). According to the configuration, at least one heat-dissipation protrusion is provided on the board on which the semiconductor element is mounted facedown, in such a manner that the protrusion is opposed to the semiconductor element with a little space therebetween. Further, a heat conductive insulator is filled in a space between the semiconductor element and the heat-dissipation protrusion.
Hereinafter, a method for manufacturing the semiconductor device of a conventional example will be described with reference to FIG. 13. FIG. 13 is a cross-sectional view of the semiconductor device of the conventional example.
In FIG. 13, conductive wirings 42 and a heat-dissipation conductive wiring 43 are formed on a wiring board 41. Heat-dissipation protrusions 44 are formed on the heat-dissipation conductive wiring 43. A semiconductor element 45 is flip-chip mounted on the wiring board 41 via element electrodes 46 of the semiconductor element 45 and connecting protrusion electrodes 47 formed on the element electrodes 46.
A reference numeral 48 illustrated by a dotted line refers to an active element region of the semiconductor element 45. A ground electrode 49 is provided on the active element region 48. A surface passivation film 50 is formed on a surface of the semiconductor element 45. A heat conductive insulator 51 is filled between the semiconductor element 45 and the wiring board 41.
According to the configuration described above, heat generated in the active element region 48 is allowed to be diffused in a horizontal direction by the ground electrode 49, dissipated via the heat conductive insulator 51, and then dissipated from the heat-dissipation protrusions 44 through the heat-dissipation conductive wiring 43 to the wiring board 41. Further, since the heat-dissipation protrusions 44 and the semiconductor element 45 are not connected, there is an advantage of reducing variations in electric characteristics of the active element region 48, as compared with a general heat dissipation configuration (for example, see JP 2000-286368 A (Patent Document 2)) shown in FIG. 14.
The semiconductor device of FIG. 14 has a heat dissipation configuration in which the semiconductor element 45 and the wiring board 41 are connected by the connecting protrusion electrodes 47. Because of this, variations in electric characteristics of the active element region 48 occur due to the load at the time of the flip-chip mounting of the semiconductor element 45 on the wiring board 41 or the stress to the active element region 48 caused by the difference in thermal expansion coefficient between the semiconductor element 45 and the wiring board 41 after the mounting. On the contrary, the configuration such as shown in FIG. 13 in which the heat-dissipation protrusions 44 and the semiconductor element 45 are not connected reduces the occurrence of such a stress.    [Patent Document 1] JP 10-65072 A    [Patent Document 2] JP 2000-286368 A